Tapping mode atomic force microscopy of the hyaluronan derivative, hylan A

M. K. Cowman, M. Li, A. Dyal, E. A. Balazs

Research output: Contribution to journalArticlepeer-review


Hylan A, a water-soluble hyaluronan derivative with enhanced molecular weight attributed to protein-mediated crosslinks, has been examined by tapping mode atomic force microscopy (TMAFM). Hylan A was deposited on mica from dilute aqueous solution and imaged in air through a thin layer of adsorbed water. Isolated chains, drawn into extended forms to varying degrees by the movement of a droplet interface across the surface ('molecular combing'), were observed. The majority of the extended chains could be characterized as long linear single-stranded molecules, as is observed for hyaluronan. In a smaller number of observations on extended hylan A, it was possible to observe apparent connections between two chains, presumably mediated by covalent linkage via protein. Hylan A was also commonly observed in less extended forms. Isolated chains of this type often exhibited intramolecular association, the simplest form of which was antiparallel double-stranded (probably double-helical) junction zones. More extensive intramolecular association, via intermittent double- or multi-stranded connections, led to a fenestrated appearance. Intermolecular association was also observed, leading to the formation of network-like matrices. The variety and types of structures observed for hylan A by TMAFM were in excellent agreement with predictions based on physicochemical studies of both hylan A and hyaluronan.

Original languageEnglish (US)
Pages (from-to)229-235
Number of pages7
JournalCarbohydrate Polymers
Issue number3
StatePublished - Mar 2000

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry


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